AB0429 SAFETY AND OBSTETRIC OUTCOMES OF BELIMUMAB IN SYSTEMIC LUPUS ERYTHEMATOSUS-ASSOCIATED IMMUNE THROMBOCYTOPENIC PURPURA PATIENTS WITH PREGNANCY
Authors: T. J. Lee, W. H. Tsai, S. C. Hsieh
Journal: Annals of the Rheumatic Diseases (2022)

Background Immune thrombocytopenia purpura (ITP) is not uncommon in systemic lupus erythematosus (SLE) patients and may lead to severe complications during pregnancy, such as pregnancy loss, and peripartum hemorrhage. 1 However, the treatment options during pregnancy was limited due to fetal safety concerns. Belimumab was approved for SLE and appeared to be safe in pregnant patients 2 . A phase II trial also reported efficacy of rituximab-belimumab combination in treating ITP 3 . However, the safety, influence on pregnancy outcomes, and effects on ITP in SLE patients with pregnancy was unclear. Objectives To evaluate the safety and obstetrics outcomes of SLE patients with pregnancy receiving belimumab for ITP. Methods This was a retrospective study in National Taiwan University Hospital. Eligible patients were more than 20 years old, had history of ITP, and fulfilled either the 1997 American College of Rheumatology or 2012 Systemic Lupus International Collaborating Clinics classification criteria. The belimumab was administered at 400 mg every 3-4 weeks. The serial full blood counts and immunological markers, unintended hospitalizations, infection episodes, pregnancy complications, and pregnancy outcomes were recorded. Results From April 2018 to November 2021, 7 SLE patients were identified. The median (IQR) age at conception was 35.6 (33.0 - 39.5) years. Three (43%) patients had secondary antiphospholipid syndrome, and none had lupus nephritis. The median (IQR) platelet count at conception was 187,000 (146,000 - 195,000) per microliter. The median (IQR) cycle of belimumab was 5 (4.5 - 8.5). Successful delivery was achieved in all patients. The median (IQR) gestational age was 36 (34 - 37) weeks, and four (57%) patients had preterm labor. The median birth weight was 2362 (2269-2477) grams, and three (43%) were small for gestational age. Pre-eclampsia developed in one patient, and none had premature preterm rupture of membrane or peripartum infections, or postpartum hemorrhage. The median platelet count at labor was 75,000 (59,000 - 116,000) per microliter. During the pregnancy, severe thrombocytopenia with a platelet counts less than 10000 per microliter occurred in two (29%) patients, and one received prophylactic preoperative platelet transfusion. None of the patients had major or minor bleeding episodes throughout the pregnancy. Remarkably, one patient developed severe thrombocytopenia to 15,000 per microliter in the first trimester of pregnancy, and the platelet count recovered to normal range after 4 doses of belimumab administration. (Figure 1) Figure 1. Serial blood platelet count during pregnancy in one patient. Arrow: belimumab 400 mg infusion. During the pregnancy courses, no patient developed bacterial infections, two (29%) patients developed viral infections (one with upper respiratory tract infection and the other with acute gastroenteritis), and two (29%) had herpes zoster reactivation, which resolved smoothly after five-day course of oral valacyclovir. Conclusion The belimumab appeared to be safe in ITP patients with pregnancy, with no obvious increase in the infections and obstetric complications. Based on these observations, belimumab may be considered as one of the pharmacological options for SLE with ITP patients during pregnancy. References [1]Xu X, Liang MY, Wang JL, et al. Clinical features and outcome of pregnancy with SLE-associated thrombocytopenia. J Matern Fetal Neonatal Med 2016;29(5):789-94. doi: 10.3109/14767058.2015.1018169 [2]Kao JH, Lan TY, Lu CH, et al. Pregnancy outcomes in patients treated with belimumab: Report from real-world experience. Semin Arthritis Rheum 2021;51(5):963-68. doi: 10.1016/j.semarthrit.2021.06.005 [3]Mahévas M, Azzaoui I, Crickx E, et al. Efficacy, safety and immunological profile of combining rituximab with belimumab for adults with persistent or chronic immune thrombocytopenia: results from a prospective phase 2b trial. Haematologica 2021;106(9):2449-57. doi: 10.3324/haematol.2020.259481 Disclosure of Interests None declared